Fuel injection advance angle control apparatus

摘要

In a distribution type fuel injection system, the injection advance angle, or the relative angular position at which fuel injection begins, is controlled by a first spring loaded piston (44). The spring force is opposed by pressurized fuel from a pump (14), the pressure increasing with engine speed. A second spring loaded piston (49) moves the first piston (44) to an advanced position for starting the engine and is retracted when the fuel pressure reaches a certain value to retard the advance angle in an idling speed range. The fuel pressure moves the first piston (44) to progressively advance the angle in a higher speed range. An O-ring (61) is provided to an end of the second piston (49) which abuts against an end wall (53) so that the fluid pressure receiving area of the second piston (49) is small when the second piston (49) abuts against the end wall (53) but is greater when the second piston (49) is moved away from the end wall (53). The effect is that the second piston (49) is prevented from moving and retarding the advance angle until the engine speed and fuel pressure reach a relatively high value upon starting of the engine. Thereafter, the advance angle will be retarded upon a return of the engine speed to the idling range.